1. Field of Invention
Aspects of this invention relate generally to the field of atmospheric drag reduction, and more particularly to an apparatus for reducing drag on vehicles.
2. Background of the Invention
When a vehicle is in motion, a low pressure area generally forms at the rear of the vehicle, and the low pressure area may result in increased drag. The increased drag can increase resistance to the motion of the vehicle and force the engine of the vehicle to work harder, and as a result reduce mileage, among other things. The increased drag is often aggravated by the shape of the vehicle. For example, the square-shaped rear end of a semi-tractor trailer may cause far more drag than the round-shaped end of a sports car.
There have been a number of drag reducing devices described in the related art. For example, U.S. Pat. No. 5,280,990 to Rinard (“Vehicle Drag Reduction System,” issued on Jan. 25, 1994) describes fixed-position mounted vanes to direct air to the rear of a semi-tractor trailer. Similar devices are found in U.S. Pat. No. 3,999,797 to Kirsch et al. (“Airvane Device for Bluff Vehicles and the Like,” issued on Dec. 28, 1976) and U.S. Pat. No. 3,960,402 to Keck (“Vehicle Flow Direction Vanes,” issued on Jun. 1, 1976).
U.S. Patent Application Publication No. US2004/0256885 to Bui (“Rear Spoiler With Motorized Vertical and Angle Adjustability,” published on Dec. 23, 2004), which provides an adjustable rear spoiler that comprises a wing-like mechanism for trucks, has an electric motor actuator for transmitting rotational motion to a worm gear box assembly, along with a wing unit and wing mounting brackets attached to upper linkage supports to create pivotal angle adjustments.
U.S. Pat. No. 6,045,095 to Parrish, IV (“Vane-Airfoil Combination,” issued on Apr. 4, 2000) shows a vane-airfoil combination that comprises a rotating set of vanes located in front of the leading edge of the airfoil assembly. WIPO Application No. W092/19485 to Eliahou (“Vehicle Streamlining Device for Pressure Drag Reduction,” published on Nov. 12, 1992) discloses a device for diverting air at the rear of a trailer that comprises a flap for streamlining a vehicle to reduce drag. The flap is raised or lowered by an actuator connected to the vehicle speedometer. U.S. Pat. No. 1,714,609 to Massey (“Airplane,” issued on May 25, 1928) shows a dual airfoil for vehicles that comprises a pair of airfoils that provide lift and have forward and rear positions. U.S. Pat. No. 1,913,169 to Martin (“Wing and Like Member for Aircraft,” issued on Jun. 6, 1933) provides a combination triple airfoil for vehicles that provide lift and reduce drag and have staggered positions relative to one another.
U.S. Pat. No. 4,810,022 to Takagi et al. (“Automotive Vehicle With Adjustable Aerodynamic Accessory and Control Therefor,” issued on Mar. 7, 1989) discloses an adjustable aerodynamic spoiler with a controller that has spoiler settings regulated automatically by sensed driving conditions, such as vehicle speed, crosswinds and the like.